RESUMEN
A method is described to determine the depth distribution of buried activity offering an alternative to conventional soil sampling and laboratory analysis by in situ measurements with small detectors inserted into the ground. As a demonstration of the method small-scale variations in the distribution of (137)Cs in a riparian marsh in central-eastern Sweden are determined using lanthanum bromide detectors (LaBr3). The results show variations of the activity ranging between 400 and 2200 kBq/m² over an area not exceeding 350 m². The decrease of the average activity since 2003 coincides with the physical decay indicating that no net redistribution of activity into this part of the marsh has occurred during the intervening years.
Asunto(s)
Radioisótopos/análisis , Contaminantes Radiactivos del Suelo/análisis , Radioisótopos de Cesio/análisis , Métodos , SueciaRESUMEN
A laboratory for measuring low-level radioactivity has been built at the AlbaNova University Center in Stockholm. Low-level concrete in combination with a 5 cm iron lining provide an average photon fluency rate from terrestrial sources at least a factor of 40 below that in the common laboratories of the Center. The radon activity inside the laboratory has been measured to (3+/-2) Bq m(-3). Material considerations are discussed. Construction and performance of the laboratory, as well as the present instrumentation, is described.